1. Field of the Invention
This invention relates to a cylinder head for a direct fuel injected engine, and more particularly to an improved cylinder head in which heat is distributed uniformly therein.
2. Description of Related Art
In all fields of engine design, there is an increasing emphasis on obtaining more effective emission control, better fuel economy and, at the same time, continued high or higher power output. This trend has resulted in the substitution of fuel injection systems for carburetors as the engine charge former. In the common systems conventionally used, fuel is injected into an intake air manifold.
In order to obtain still further improvement, direct injection systems are being considered. These systems inject fuel directly into a combustion chamber and thus have significant potential advantages. With direct fuel injection systems, the fuel must be injected directly into the combustion chamber, and consequently a fuel injector is disposed on a cylinder head that defines the combustion chamber.
When an engine charge is burnt in the combustion chamber, extremely high temperature is generated and conducted to the cylinder head. The cylinder head, therefore, has a water jacket therein to remove the heat promptly. However, because the fuel injector is disposed onto the cylinder head as noted above, it is likely to displace the water jacket in a portion of the cylinder head. The portion of the cylinder head that bears the fuel injector, thus, hold heat more than the other portions. The temperature distribution in the cylinder head thus is not uniform.
The cylinder head encircles a primary portion of the combustion chamber. As a result, the combustion state in the combustion chamber tends to be unstable, i.e., inconsistent. The engine consequently runs rough. This tendency is noticeable if the fuel injector is not positioned directly above the center of the combustion chamber.